Publications
185 results found
Hills, Florin N, Fennell PS, 2016, Decarbonising the cement sector: a bottom-up model for optimising carbon capture application in the UK, Journal of Cleaner Production, Vol: 139, Pages: 1351-1361, ISSN: 0959-6526
Industrial processes such as Portland cement manufacture produce a large proportion of anthropogenic carbon dioxide and significantly reducing their emissions could be difficult or expensive without carbon capture and storage. This paper explores the idea of synchronising shutdowns for carbon capture and storage installation with major shutdowns required to refurbish major process units at industrial sites. It develops a detailed bottom-up model for the first time and applies it to the United Kingdom’s cement industry. This research demonstrates that several policy and technology risks are not identified by the top-down models and it highlights the importance of reducing shut-down times for capture plant construction. Failure to do so could increase installation costs by around 10 per cent. This type of approach, which is complementary to top-down modelling, and the lessons learned from it can be applied to other capital- and energy-intensive industries such as primary steel production. It provides important information about what actions should be prioritised to ensure that carbon capture and storage can be applied without extra unnecessary shutdowns which would increase the overall cost of carbon dioxide mitigation and could delay action, increasing cumulative emissions as well.
Fennell PS, Zhang Z, Hills T, et al., 2016, Spouted Bed Reactor for kinetic Measurements of Reduction of Fe2O3 in a CO2/CO Atmosphere Part I - Atmospheric Pressure Measurements and Equipment Commissioning, Chemical Engineering Research & Design, Vol: 114, Pages: 307-320, ISSN: 1744-3563
A high pressure and high temperature spouted bed reactor, operating in fluidisation mode, has been designed and validated at low pressure for the study of gas-solid reaction kinetics. Measurements suggested the bed exhibited a fast rate of gas interchange between the bubble and particulate phases. Pressurised injection of the particles to the bottom of the bed allowed the introduction of solid reactants in a simple and controlled manner. The suitability of the reactor for the purpose of kinetic studies was demonstrated by investigation of the intrinsic kinetics of the initial stage of the reduction of Fe2O3 with CO over multiple cycles for chemical looping.Changes of pore structure over the initial cycles were found to affect the observed kinetics of the reduction. The initial intrinsic rate constant of the reduction reaction (ki) was measured by using a kinetic model which incorporated an effectiveness factor. The uncertainty arising from the measurement of particle porosity in the model was compensated for by the tortuosity factor. The average activation energy obtained for cycles three to five was 61 ± 8 kJ/mol, which is comparable with previous studies using both fluidised beds and thermogravimetry.
Mechleri E, fennell P, Mac Dowell N, 2016, Flexible operation strategies for coal- and gas-CCS power stations under the UK and USA markets, 13th Greenhouse Gas Control Technologies (GHGT) conference
Sikarwar VS, Zhao M, Clough P, et al., 2016, An overview of advances in biomass gasification, Energy and Environmental Science, Vol: 9, Pages: 2939-2977, ISSN: 1754-5692
Biomass gasification is a widely used thermochemical process for obtaining products with more value and potential applications than the raw material itself. Cutting-edge, innovative and economical gasification techniques with high efficiencies are a prerequisite for the development of this technology. This paper delivers an assessment on the fundamentals such as feedstock types, the impact of different operating parameters, tar formation and cracking, and modelling approaches for biomass gasification. Furthermore, the authors comparatively discuss various conventional mechanisms for gasification as well as recent advances in biomass gasification. Unique gasifiers along with multi-generation strategies are discussed as a means to promote this technology into alternative applications, which require higher flexibility and greater efficiency. A strategy to improve the feasibility and sustainability of biomass gasification is via technological advancement and the minimization of socio-environmental effects. This paper sheds light on diverse areas of biomass gasification as a potentially sustainable and environmentally friendly technology.
Hosseini S, Soltani SM, Fennell PS, et al., 2016, Production and applications of electric-arc-furnace slag as solid waste in environmental technologies: a review, Environmental Technology Reviews, Vol: 5, Pages: 1-11, ISSN: 2162-2515
© 2016, © 2016 Informa UK Limited, trading as Taylor & Francis Group. Slag, a by-product of steelmaking industries, has invaluable potentials for various environmental applications. Slag is generally produced in different types of furnaces working under various operating conditions and contains alumina, calcium oxide, silica and so on. Physical and chemical properties of a typical slag dictate the distinct methods of slag solidification including air cooling, steam introduction and injection of additives. Owing to this uniquely-widespread range of properties, slags are being increasingly considered attractive materials in a broad range of applications. They are widely used in transportation industry, construction, and cement manufacturing as well as wastewater and water treatment. This makes slag an important substitute for natural resources, leading to significant minimization in natural resource utilization. This paper walks through a comprehensive essay of steelmaking slag retained in a wide range of furnaces, their modifications and their applications alike.
Blamey J, Fennell P, Anthony E, et al., 2016, A shrinking core model for steam hydration of CaO-based sorbents cycled for CO2 capture, Chemical Engineering Journal, Vol: 291, Pages: 298-305, ISSN: 1873-3212
Calcium looping is a developing CO2 capture technology. It is based on the reversiblecarbonation of CaO sorbent, which becomes less reactive upon cycling. One method ofincreasing the reactivity of unreactive sorbent is by hydration in the calcined (CaO) form.Here, sorbent has been subjected to repeated cycles of carbonation and calcination within asmall fluidised bed reactor. Cycle numbers of 0 (i.e., one calcination), 2, 6 and 13 have beenstudied to generate sorbents that have been deactivated to different extents. Subsequently,the sorbent generated was subjected to steam hydration tests within a thermogravimetricanalyser, using hydration temperatures of 473, 573 and 673 K. Sorbents that had beencycled less prior to hydration hydrated rapidly. However, the more cycled sorbents exhibitedbehaviour where the hydration conversion tended towards an asymptotic value, which is likelyto be associated with pore blockage. This asymptotic value tended to be lower at higherhydration temperatures; however, the maximum rate of hydration was found to increase withincreasing hydration temperature. A shrinking core model has been developed and applied to 2the data. It fits data from experiments that did not exhibit extensive pore blockage well, butfits data from experiments that exhibited pore blockage less well
Hills T, Leeson D, Florin N, et al., 2016, Carbon capture in the cement industry: technologies, progress, and retrofitting, Environmental Science & Technology, Vol: 50, Pages: 368-377, ISSN: 0013-936X
Several different carbon-capture technologies have been proposed for use in the cement industry. This paper reviews their attributes, the progress that has been made toward their commercialization, and the major challenges facing their retrofitting to existing cement plants. A technology readiness level (TRL) scale for carbon capture in the cement industry is developed. For application at cement plants, partial oxy-fuel combustion, amine scrubbing, and calcium looping are the most developed (TRL 6 being the pilot system demonstrated in relevant environment), followed by direct capture (TRL 4–5 being the component and system validation at lab-scale in a relevant environment) and full oxy-fuel combustion (TRL 4 being the component and system validation at lab-scale in a lab environment). Our review suggests that advancing to TRL 7 (demonstration in plant environment) seems to be a challenge for the industry, representing a major step up from TRL 6. The important attributes that a cement plant must have to be “carbon-capture ready” for each capture technology selection is evaluated. Common requirements are space around the preheater and precalciner section, access to CO2 transport infrastructure, and a retrofittable preheater tower. Evidence from the electricity generation sector suggests that carbon capture readiness is not always cost-effective. The similar durations of cement-plant renovation and capture-plant construction suggests that synchronizing these two actions may save considerable time and money.
Gonzalez B, Blamey J, Al-Jeboori MJ, et al., 2015, Additive effects of steam addition and HBr doping for CaO-based sorbents for CO2 capture, Chemical Engineering and Processing: Process Intensification, Vol: 103, Pages: 21-26, ISSN: 1873-3204
Calcium looping is a developing CO2 capture and storage technology that employs the reversible carbonation of CaO (potentially derived from natural limestone). The CO2 uptake potential of CaO particles reduces upon repeated reaction, largely through loss of reactive surface area and densification of particles. Doping of particles has previously been found to reduce the rate of decay of CO2 uptake, as has the introduction of steam into calcination and carbonation stages of the reaction. Here, the synergistic effects of steam and doping, using an HBr solution, of 5 natural limestones have been investigated. The enhancement to the CO2 uptake was found to be additive, with CO2 uptake after 13 cycles found to be up to 3 times higher for HBr-doped limestones subjected to cycles of carbonation and calcination in the presence of 10% steam, in comparison to natural limestone cycled in the absence of steam. A qualitative discussion of kinetic data is also presented.
Blamey J, Al-Jeboori MJ, Manovic V, et al., 2015, CO2 capture by calcium aluminate pellets in a small fluidized bed, Fuel Processing Technology, Vol: 142, Pages: 100-106, ISSN: 1873-7188
Synthetic pellets made using calcium aluminate cement and quicklime have been examined in a small fluidized bed reactor to determine their performance in cyclic CO2 capture for up to 20 calcination/capture cycles. Two batches were examined one a “fresh” batch, and the second an “aged” batch of pellets and their performance was compared with the original parent limestone. Carbonation was carried out at 650 °C and calcination at 900 °C, both with 15% CO2, balance N2, as a synthetic flue gas. Experiments were also performed with and without steam in the flue gas and showed that steam always improved capture performance. In addition, there was no major attrition associated with the pellets, and pellets tended to perform better in terms of carbon capture than the parent limestone.
Song Q, Liu W, Cao S, et al., 2015, Nanostructured metal oxides for chemical looping processes, Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Mukherjee S, Kumar P, Yang A, et al., 2015, Energy and exergy analysis of chemical looping combustion technology and comparison with pre-combustion and oxy-fuel combustion technologies for CO2 capture, Journal of Environmental Chemical Engineering, Vol: 3, Pages: 2104-2114, ISSN: 2213-3437
Carbon dioxide (CO2) emitted from conventional coal-based power plants is a growing concern for the environment. Chemical looping combustion (CLC), pre-combustion and oxy-fuel combustion are promising CO2 capture technologies which allow clean electricity generation from coal in an integrated gasification combined cycle (IGCC) power plant. This work compares the characteristics of the above three capture technologies to those of a conventional IGCC plant without CO2 capture. CLC technology is also investigated for two different process configurations—(i) an integrated gasification combined cycle coupled with chemical looping combustion (IGCC–CLC), and (ii) coal direct chemical looping combustion (CDCLC)—using exergy analysis to exploit the complete potential of CLC. Power output, net electrical efficiency and CO2 capture efficiency are the key parameters investigated for the assessment. Flowsheet models of five different types of IGCC power plants, (four with and one without CO2 capture), were developed in the Aspen plus simulation package. The results indicate that with respect to conventional IGCC power plant, IGCC–CLC exhibited an energy penalty of 4.5%, compared with 7.1% and 9.1% for pre-combustion and oxy-fuel combustion technologies, respectively. IGCC–CLC and oxy-fuel combustion technologies achieved an overall CO2 capture rate of ∼100% whereas pre-combustion technology could capture ∼94.8%. Modification of IGCC–CLC into CDCLC tends to increase the net electrical efficiency by 4.7% while maintaining 100% CO2 capture rate. A detailed exergy analysis performed on the two CLC process configurations (IGCC–CLC and CDCLC) and conventional IGCC process demonstrates that CLC technology can be thermodynamically as efficient as a conventional IGCC process.
Zhang J, Fennell PS, Trusler JPM, 2015, Density and Viscosity of Partially Carbonated Aqueous Tertiary Alkanolamine Solutions at Temperatures between (298.15 and 353.15) K, Journal of Chemical and Engineering Data, Vol: 60, Pages: 2392-2399, ISSN: 1520-5134
The density and viscosity of partially carbonatedaqueous solutions of either 2-dimethylaminoethanol or 2-diethylaminoethanolwere measured over a temperature range of (298.15 to353.15) K with alkanolamine mass fractions of 0.15 to 0.45.Correlations were developed to represent the density and viscosityof these solutions as a function of amine concentration, CO2 loading,and temperature. For the density, the correlation represents theexperimental data to within ± 0.2 %, while the viscosity data werecorrelated to within ± 4 %. The data and models reported in thispaper will help facilitate a better understanding of the performance ofthese amines in CO2 capture processes, especially in relation to masstransfer and hydrodynamic calculations.
Mukherjee S, Kumar P, Yang A, et al., 2015, A systematic investigation of the performance of copper-, cobalt-, iron-, manganese- and nickel-based oxygen carriers for chemical looping combustion technology through simulation models, CHEMICAL ENGINEERING SCIENCE, Vol: 130, Pages: 79-91, ISSN: 0009-2509
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- Citations: 35
Blamey J, Manovic V, Anthony EJ, et al., 2015, On steam hydration of CaO-based sorbent cycled for CO2 capture, FUEL, Vol: 150, Pages: 269-277, ISSN: 0016-2361
Hills TP, Gordon F, Florin NH, et al., 2015, Statistical analysis of the carbonation rate of concrete, CEMENT AND CONCRETE RESEARCH, Vol: 72, Pages: 98-107, ISSN: 0008-8846
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- Citations: 42
Fennell P, 2015, Economics of chemical andcalcium looping, ) Capture, Pages: 39-48, ISBN: 9780857092434
Why choose chemical looping or calcium looping? Pure and simple economics. Should the emission of CO2 be regulated, existing power stations will need to be retrofitted with CO2 capture (Ca-looping is a candidate here), and new power stations will need to be built (chemical looping could be a candidate). As regulation of CO2 emissions comes closer, the cost to operate plants has become more of an issue for operators, with renewed interest in second- and third-generation technologies. Here, the cost of CO2 avoided is used as the primary metric by which to judge these technologies. A number of literature sources have been consulted, and costs have been rebased to 2011 prices to allow comparison on a fair basis. The price for calcium looping has been roughly estimated to be $2011 26±10, whereas that for chemical looping has been estimated to be $2011 20-30 (based on application to a power station). A key message is that it is extremely important to consider how the financing has been accounted for in any analysis, prior to quoting a figure.
Fennell P, 2015, Calcium and chemical looping technology: An introduction, ) Capture, Pages: 1-14, ISBN: 9780857092434
Carbon capture and storage (CCS) is a key technology to assist in the decarbonisation of the global economy. However, current front-running CCS technologies require a significant amount of energy to operate, and would require the electricity output of a power station to which they were fitted to increase by 22%-26%. Because of this, alternative CCS technologies have been proposed and are in the process of scaling up to the point where they could be fitted on either fossil-fuelled power stations or large industrial processes. Calcium and chemical looping (together comprising high-temperature looping cycles) are two of the most promising technologies, benefitting from high efficiency and reactors that are available at scale (essentially) off the shelf. Careful heat integration and consideration of exergy destruction is one of the main reasons for the high efficiencies of these processes. The requirement for low toxicity and high durability, reactivity and capacity is discussed in the context of what makes a good carrier of either CO2 or O2 for use in calcium or chemical looping. There are a number of industrial processes (e.g. iron and steel production, cement manufacture and steam generation) forwhich there are niche applications of high-temperature looping cycles.
Fennell PS, Anthony EJ, 2015, Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO<inf>2</inf>) Capture, ISBN: 9780857092434
Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO2) Capture reviews the fundamental principles, systems, oxygen carriers, and carbon dioxide carriers relevant to chemical looping and combustion. Chapters review the market development, economics, and deployment of these systems, also providing detailed information on the variety of materials and processes that will help to shape the future of CO2 capture ready power plants.
Mehleri ED, Bhave A, Shah N, et al., 2015, Techno-economic assessment and environmental impacts of Mineral Carbonation of industrial wastes and other uses of carbon dioxide, Pages: 576-585
In this contribution, we present the results of an in-depth techno-economic analysis of some leading CO2 capture and utilisation (CCU) and conversion (CCC) options. Specifically, we consider CO2 conversion to methanol, formic acid and urea (CCC) in addition to mineral carbonation of industrial wastes (CCU). We compare the CCC and CCU options using a range of key performance indicators (KPIs), including 2nd law efficiency, CO2 avoided and tonneCo2/tonneproduct. The results indicate that CCU and CCC technologies are unlikely to provide a significant contribution to mitigating anthropogenic climate change. The primary bottleneck to industrial scale deployment of CCC technologies is likely to be the cost effective availability of low carbon-hydrogen in the case that the conversion option requires hydrogen. Further, we find that mineral carbonation may have niche applications in the context of industrial waste remediation but the large scale deployment of this technology as a substitute for the geological sequestration of CO2 is unlikely to be either cost effective or scalable. Moreover, although formic acid offers attractive economic profiles, we note that this process is at a lower TRL (TRL 4-5). Thus, we conclude that CCC and CCU technologies are only likely to be viable at scale in the event that substantial subsidies are available to offset the high costs associated with producing renewable hydrogen and the thermodynamic cost associated with processing such a stable molecule.
Florin N, Boot-Handford M, Fennell P, 2015, Calcium looping technologies for gasification and reforming, CALCIUM AND CHEMICAL LOOPING TECHNOLOGY FOR POWER GENERATION AND CARBON DIOXIDE (CO2) CAPTURE, Editors: Fennell, Anthony, Publisher: WOODHEAD PUBL LTD, Pages: 139-152, ISBN: 978-0-85709-243-4
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- Citations: 3
Fennell PS, Anthony EJ, 2015, Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO<sub>2</sub>) Capture Preface, CALCIUM AND CHEMICAL LOOPING TECHNOLOGY FOR POWER GENERATION AND CARBON DIOXIDE (CO2) CAPTURE, Editors: Fennell, Anthony, Publisher: WOODHEAD PUBL LTD, Pages: XIX-XIX, ISBN: 978-0-85709-243-4
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Liu W, Ismail M, Dunstan MT, et al., 2015, Inhibiting the interaction between FeO and Al<sub>2</sub>O<sub>3</sub> during chemical looping production of hydrogen, RSC ADVANCES, Vol: 5, Pages: 1759-1771, ISSN: 2046-2069
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- Citations: 67
Blamey J, Yao JG, Arai Y, et al., 2015, Enhancement of natural limestone sorbents for calcium looping processes, Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO2) Capture, Editors: Fennell, Anthony, Publisher: Woodhead (Elsevier), Pages: 73-105, ISBN: 978-0-85709-243-4
Calcium looping (CaL) is a high-temperature solid looping cycle that can be used for post- or precombustion capture of CO2. Limestone (predominantly CaCO3), a cheap and abundant material, is purged in quite large quantities to ensure high reactivity, since it degrades significantly over time. The loss in reactivity is caused by either physical effects, for example, sintering or attrition, or chemical means, for example, the competing side reaction with SO2 from fuel. Much of the research has been of processes to improve sorbent behaviour; investigated here are the reactivation techniques of hydration, recarbonation and pelletization, as well as the sorbent-enhancement techniques of doping and thermal pretreatment.
Blamey J, Anthony EJ, 2015, End use of lime-based sorbents from calcium looping systems, Calcium and Chemical Looping Technology for Power Generation and Carbon Dioxide (CO2) Capture, Editors: Fennell, Anthony, Publisher: Woodhead (Elsevier), Pages: 153-169, ISBN: 978-0-85709-243-4
Calcium looping (CaL) is a technology that uses a recyclable solid. However, all solid sorbents eventually require either regeneration or replacement, as they are degraded by physical or chemical processes. Implicit in the CaL approach is that the primary sorbent (limestone) is less expensive than the carefully manufactured sorbents associated with chemical looping, for instance. This means that larger amounts of spent sorbents are likely to be produced and will require treatment. This chapter looks at the various possibilities of using spent sorbents produced by CaL processes, focusing particularly on the power industry, steel and cement production.
Zhao M, Shi J, Zhong X, et al., 2014, A novel calcium looping absorbent incorporated with polymorphic spacers for hydrogen production and CO2 capture, Energy and Environmental Science, Vol: 7, Pages: 3291-3295, ISSN: 1754-5692
High temperature looping cycles can be used to produce hydrogen or capture CO2 from power stations, though sintering of absorbents is frequently a problem, reducing reactivity. In this work we develop materials, in which the crystal structure and volume of polymorphic materials change with temperature, as active spacers to reduce sintering.
Boot-Handford ME, Florin NH, Kandiyoti R, et al., 2014, Assessing the suitability of different biomass feedstocks for processing via gasification, 248th National Meeting of the American-Chemical-Society (ACS), ISSN: 0065-7727
Boot-Handford ME, Zhang Z, Fennell PS, et al., 2014, Investigating the performance of Fe- and Cu-based oxygen carriers for pressurised chemical-looping combustion of gaseous fuels, 248th National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Gschwend FJV, Hallett JP, Fennell PS, 2014, Towards a cost efficient production of fuels from lignocellulosic biomass using ionic liquids, 248th National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727
Manovic V, Fennell P, 2014, EJ Anthony honor issue, FUEL, Vol: 127, Pages: 1-3, ISSN: 0016-2361
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